ABSTRACT
Solutions are homogeneous mixtures of one or more solutes dispersed in a suitable solvent or a mixture of mutually miscible solvents. A solution composed of only two substances is a binary solution. The components making up a binary solution are termed solvent and the solute depending on their relative proportions (component in lower proportion is termed solute). Pharmaceutical solutions are used for many routes of administration, including oral, rectal, vaginal, ophthalmic, parenteral, and otic. The most common solution dosage form is the oral liquid, which includes aqueous solutions, syrups, and elixirs. The physicochemical and stability characteristics of the active drug determine whether oral solution dosage forms can be prepared. The drug’s concentrations and solubility in various solvents will dictate the type of dosage form to prepare. For example, if the drug is water soluble, a syrup can be prepared. However, if it is soluble in a water-alcohol-glycerin cosolvent system, an elixir is appropriate. Drugs are commonly given in solution in cough/cold remedies and in medications for the young and elderly.
